Literary usage of Spiker

Below you will find example usage of this term as found in modern and/or classical literature:

1.Letters of Alexander Von Humboldt Written Between the Years 1827 and 1858 to by Alexander von Humboldt, Karl August Varnhagen von Ense, Ludmilla Assing (1860)"I ana going to-morrow morning with the King to Potsdam for six or seven days.
Your grateful and unreadable friend, LV. A. v. HUMBOLDT. HUMBOLDT TO spiker. ..."